Control of widely tunable SSG-DBR lasers for dense wavelengthdivision multiplexing

This paper presents a general discussion on the control of widely tunable super structure grating distributed Bragg reflector (SSG-DBR) lasers. A feedback control scheme is presented that ensures frequency stability and accuracy (better than ±0.5 GHz), as well as high side mode suppression ratio (>35 dB). The active section voltage is monitored to maintain mode stability and a highly stable Fabry-Perot etalon is used as a reference to lock the laser frequency to a specific ITU channel. It is shown that stability can even be maintained when directly modulating the laser at 1.244 Gb/s. Furthermore, a characterization scheme is demonstrated that uses the voltage monitoring to generate a look-up table of operation points very efficiently and accurately. For all operation points, the frequency accuracy is better than ±0.5 GHz and the side mode suppression ratio is above 35 dB